third_party/pigweed/repo/pw_cpu_exception_cortex_m/py/exception_analyzer_test.py

   1 #!/usr/bin/env python3
   2 # Copyright 2020 The Pigweed Authors
   3 #
   4 # Licensed under the Apache License, Version 2.0 (the "License"); you may not
   5 # use this file except in compliance with the License. You may obtain a copy of
   6 # the License at
   7 #
   8 #     https://www.apache.org/licenses/LICENSE-2.0
   9 #
  10 # Unless required by applicable law or agreed to in writing, software
  11 # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  12 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  13 # License for the specific language governing permissions and limitations under
  14 # the License.
  15 """Tests dumped Cortex-M CPU state."""
  16
  17 import unittest
  18 import os
  19
  20 from pw_protobuf_compiler import python_protos
  21 from pw_cli import env
  22 from pw_cpu_exception_cortex_m import exception_analyzer, cortex_m_constants
  23
  24 CPU_STATE_PROTO_PATH = os.path.join(
  25     env.pigweed_environment().PW_ROOT,  #pylint: disable=no-member
  26     'pw_cpu_exception_cortex_m',
  27     'pw_cpu_exception_cortex_m_protos',
  28     'cpu_state.proto')
  29
  30 cpu_state_pb2 = python_protos.compile_and_import_file(CPU_STATE_PROTO_PATH)
  31
  32 # pylint: disable=protected-access
  33
  34
  35 class BasicFaultTest(unittest.TestCase):
  36     """Test basic fault analysis functions."""
  37     def test_empty_state(self):
  38         """Ensure an empty CPU state proto doesn't indicate an active fault."""
  39         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
  40         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
  41             cpu_state_proto)
  42         self.assertFalse(cpu_state_info.is_fault_active())
  43
  44     def test_cfsr_fault(self):
  45         """Ensure a fault is active if CFSR bits are set."""
  46         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
  47         cpu_state_proto.cfsr = (
  48             cortex_m_constants.PW_CORTEX_M_CFSR_STKOF_MASK
  49             | cortex_m_constants.PW_CORTEX_M_CFSR_MUNSTKERR_MASK)
  50         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
  51             cpu_state_proto)
  52         self.assertTrue(cpu_state_info.is_fault_active())
  53
  54     def test_icsr_fault(self):
  55         """Ensure a fault is active if ICSR says the handler is active."""
  56         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
  57         cpu_state_proto.icsr = (
  58             cortex_m_constants.PW_CORTEX_M_HARD_FAULT_ISR_NUM)
  59         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
  60             cpu_state_proto)
  61         self.assertTrue(cpu_state_info.is_fault_active())
  62
  63     def test_cfsr_fields(self):
  64         """Ensure correct fields are returned when CFSR bits are set."""
  65         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
  66         cpu_state_proto.cfsr = (
  67             cortex_m_constants.PW_CORTEX_M_CFSR_STKOF_MASK
  68             | cortex_m_constants.PW_CORTEX_M_CFSR_MUNSTKERR_MASK)
  69         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
  70             cpu_state_proto)
  71         active_fields = [
  72             field.name for field in cpu_state_info.active_cfsr_fields()
  73         ]
  74         self.assertEqual(len(active_fields), 2)
  75         self.assertIn('STKOF', active_fields)
  76         self.assertIn('MUNSTKERR', active_fields)
  77
  78
  79 class ExceptionCauseTest(unittest.TestCase):
  80     """Test exception cause analysis."""
  81     def test_empty_cpu_state(self):
  82         """Ensure empty CPU state has no known cause."""
  83         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
  84         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
  85             cpu_state_proto)
  86         self.assertEqual(cpu_state_info.exception_cause(), 'unknown exception')
  87
  88     def test_unknown_exception(self):
  89         """Ensure CPU state with insufficient info has no known cause."""
  90         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
  91         # Set CFSR to a valid value.
  92         cpu_state_proto.cfsr = 0
  93         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
  94             cpu_state_proto)
  95         self.assertEqual(cpu_state_info.exception_cause(), 'unknown exception')
  96
  97     def test_single_usage_fault(self):
  98         """Ensure usage faults are properly identified."""
  99         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
 100         cpu_state_proto.cfsr = cortex_m_constants.PW_CORTEX_M_CFSR_STKOF_MASK
 101         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
 102             cpu_state_proto)
 103         self.assertEqual(cpu_state_info.exception_cause(),
 104                          'usage fault [STKOF]')
 105
 106     def test_single_usage_fault_without_fields(self):
 107         """Ensure disabling show_active_cfsr_fields hides field names."""
 108         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
 109         cpu_state_proto.cfsr = cortex_m_constants.PW_CORTEX_M_CFSR_STKOF_MASK
 110         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
 111             cpu_state_proto)
 112         self.assertEqual(cpu_state_info.exception_cause(False), 'usage fault')
 113
 114     def test_multiple_faults(self):
 115         """Ensure multiple CFSR bits are identified and reported."""
 116         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
 117         cpu_state_proto.cfsr = (
 118             cortex_m_constants.PW_CORTEX_M_CFSR_STKOF_MASK
 119             | cortex_m_constants.PW_CORTEX_M_CFSR_UNSTKERR_MASK)
 120         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
 121             cpu_state_proto)
 122         self.assertEqual(cpu_state_info.exception_cause(),
 123                          'usage fault, bus fault [UNSTKERR] [STKOF]')
 124
 125     def test_mmfar_missing(self):
 126         """Ensure if mmfar is valid but missing it is handled safely."""
 127         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
 128         cpu_state_proto.cfsr = (
 129             cortex_m_constants.PW_CORTEX_M_CFSR_MUNSTKERR_MASK
 130             | cortex_m_constants.PW_CORTEX_M_CFSR_MMARVALID_MASK)
 131         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
 132             cpu_state_proto)
 133         self.assertEqual(cpu_state_info.exception_cause(False),
 134                          'memory management fault at ???')
 135
 136     def test_mmfar_valid(self):
 137         """Validate output format of valid MMFAR."""
 138         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
 139         cpu_state_proto.cfsr = (
 140             cortex_m_constants.PW_CORTEX_M_CFSR_MUNSTKERR_MASK
 141             | cortex_m_constants.PW_CORTEX_M_CFSR_MMARVALID_MASK)
 142         cpu_state_proto.mmfar = 0x722470e4
 143         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
 144             cpu_state_proto)
 145         self.assertEqual(cpu_state_info.exception_cause(False),
 146                          'memory management fault at 0x722470e4')
 147
 148     def test_imprecise_bus_fault(self):
 149         """Check that imprecise bus faults are identified correctly."""
 150         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
 151         cpu_state_proto.cfsr = (
 152             cortex_m_constants.PW_CORTEX_M_CFSR_IMPRECISERR_MASK
 153             | cortex_m_constants.PW_CORTEX_M_CFSR_IBUSERR_MASK)
 154         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
 155             cpu_state_proto)
 156         self.assertEqual(cpu_state_info.exception_cause(False),
 157                          'imprecise bus fault')
 158
 159
 160 class TextDumpTest(unittest.TestCase):
 161     """Test larger state dumps."""
 162     def test_registers(self):
 163         """Validate output of general register dumps."""
 164         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
 165         cpu_state_proto.pc = 0xdfadd966
 166         cpu_state_proto.mmfar = 0xaf2ea98a
 167         cpu_state_proto.r0 = 0xf3b235b1
 168         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
 169             cpu_state_proto)
 170         expected_dump = '\n'.join((
 171             'pc         0xdfadd966',
 172             'mmfar      0xaf2ea98a',
 173             'r0         0xf3b235b1',
 174         ))
 175         self.assertEqual(cpu_state_info.dump_registers(), expected_dump)
 176
 177     def test_dump_no_cfsr(self):
 178         """Validate basic CPU state dump."""
 179         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
 180         cpu_state_proto.pc = 0xd2603058
 181         cpu_state_proto.mmfar = 0x8e4eb9a2
 182         cpu_state_proto.r0 = 0xdb5e7168
 183         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
 184             cpu_state_proto)
 185         expected_dump = '\n'.join((
 186             'Exception caused by a unknown exception.',
 187             '',
 188             'No active Crash Fault Status Register (CFSR) fields.',
 189             '',
 190             'All registers:',
 191             'pc         0xd2603058',
 192             'mmfar      0x8e4eb9a2',
 193             'r0         0xdb5e7168',
 194         ))
 195         self.assertEqual(str(cpu_state_info), expected_dump)
 196
 197     def test_dump_with_cfsr(self):
 198         """Validate CPU state dump with CFSR bits set is formatted correctly."""
 199         cpu_state_proto = cpu_state_pb2.ArmV7mCpuState()
 200         cpu_state_proto.cfsr = (
 201             cortex_m_constants.PW_CORTEX_M_CFSR_PRECISERR_MASK
 202             | cortex_m_constants.PW_CORTEX_M_CFSR_BFARVALID_MASK)
 203         cpu_state_proto.pc = 0xd2603058
 204         cpu_state_proto.bfar = 0xdeadbeef
 205         cpu_state_proto.mmfar = 0x8e4eb9a2
 206         cpu_state_proto.r0 = 0xdb5e7168
 207         cpu_state_info = exception_analyzer.CortexMExceptionAnalyzer(
 208             cpu_state_proto)
 209         expected_dump = '\n'.join((
 210             'Exception caused by a bus fault at 0xdeadbeef.',
 211             '',
 212             'Active Crash Fault Status Register (CFSR) fields:',
 213             'PRECISERR   Precise bus fault.',
 214             'BFARVALID   BFAR is valid.',
 215             '',
 216             'All registers:',
 217             'pc         0xd2603058',
 218             'cfsr       0x00008200',
 219             'mmfar      0x8e4eb9a2',
 220             'bfar       0xdeadbeef',
 221             'r0         0xdb5e7168',
 222         ))
 223         self.assertEqual(str(cpu_state_info), expected_dump)
 224
 225
 226 if __name__ == '__main__':
 227     unittest.main()